From the beginning, this year's race for mayor of Philadelphia has refused to stick to the script.
Just two days before the polls open for the Democratic primary, consider:
More white voters prefer a black candidate than either of his two white rivals. And one of the white contenders draws strong black support.
A business mogul came from nowhere with the city's first self-funded campaign, proving the power of cash with a vow to "buy back" City Hall from the insiders.
Television ads, always important in modern races, played an outsize role in shaping voter opinion - through sheer volume.
Two candidates with the best old-fashioned street organizations - U.S. Rep. Bob Brady, boss of the Democratic machine, and U.S. Rep. Chaka Fattah, the overwhelming early favorite, struggled for footing.
City campaign-money limits kicked in for the first time, forcing candidates to work harder to raise and spend cash. Even so, more money - nearly $20 million - sloshed into the race than in the bad old days of $100,000 donations. Independent "527" groups popped up to evade the limits.
The winning message so far, in a town traditionally averse to change, is just that: change. "The city," pollster Terry Madonna said, "is sort of at a turning point."
Randall Miller, a historian at St. Joseph's University who studies Philadelphia politics, said: "There are a lot of things happening in this election that don't fit past patterns."
Many of these trends were influenced by Tom Knox, the former insurance executive who has slipped to second place in the polls but has spent nearly $10 million of his own cash.
Former City Councilman Michael Nutter, who thumps his record of government-ethics legislation and calls for a crime emergency, surged into the lead of the Keystone Poll released last week. He had 31 percent to Knox's 21; Fattah polled 13 percent, Brady 11 and State Rep. Dwight Evans 3.
But there's still volatility in the electorate, according to the poll: A fifth of voters said they were undecided, and 41 percent of "decideds" told pollsters that they could change their minds.
The numbers cause political analysts to warn against writing off the men with the fabled organizations, Brady and Fattah.
But that traditional street muscle has been put to the test by two media-centric candidates who have done the best at casting themselves as change agents - Knox and Nutter.
"If Knox wins or even comes in a strong second, that could change the dynamics of future Philadelphia mayoral elections," Miller said. "People will see it is possible to succeed as an independent, outside the organizational structure."
Why do these five men want it so badly? They are interviewing for the ungodly 24/7 job of leading an old city of 1.4 million people, a city bursting with new commercial development but stricken with a soaring murder rate and deep pockets of poverty, run by a government barely be able to cover its employees' health insurance and pension costs, to say nothing of fighting poverty and crime.
The job's current occupant, John Street, is finishing an eight-year tenure marked forever by the corruption probe that featured an FBI bug in his office.
Yet the contest to succeed him has drawn out many of the better angels of Philadelphia's nature and - at least till now - few of the lesser ones. There have been more candidate forums and debates about real issues in this campaign than any political veterans can remember. With a few exceptions - Nutter's "outraged black man" speech, Fattah's remark that Nutter needed reminding of his blackness, and an anti-Nutter ad that the Committee of Seventy last week called "blatantly racial" - the race card hasn't been played.
Another strange thing about this campaign: For the most part, it has centered on sober discussion of issues. And not just traditional ones: The greening of the city. Support for the arts. A Committee of Seventy ethics pledge that had all five candidates renouncing nepotism and no-bid contracts in terms that would make old-time bosses twirl in their graves.
With homicides soaring, crime is the top concern - by a mile. Polls also indicate most voters think their city is on the wrong track and want change.
Madonna, director of the Keystone Poll, said Tuesday's vote shapes up as the "third most pivotal since World War II." The others: 1951, when reform Democrats ousted the GOP machine, and 1991, when Ed Rendell began pulling the city back from insolvency and ushered in Center City's rebirth.
"What's pivotal now is the neighborhoods, and they are facing problems with crime, poverty and education," said Madonna, a professor at Franklin and Marshall College. "Who gets elected matters."
And yet the high undecideds late in the game suggest a majority of the city's 761,000 registered Democrats may sit out the primary. Strategists in the campaigns estimate a turnout of 35 percent to 40 percent.
Which means the race so compelling and surprising to the chattering classes has done little to stir the masses. Which means, too, that it isn't over.
Do undecided voters break toward the candidate with momentum, Nutter? Do they get energized by a candidate's field troops? Or do they stay home?
In recent polls, undecided Democrats tended to be poorer and less educated. More women than men have been undecided, and more black voters than white voters. That could bode well for one candidate: "We're probably seeing an understatement of Fattah's support," said James Lee of Susquehanna Polling & Research.
As the rivals girded for a final push, Knox and Nutter went head to head with TV ads. Fattah and Brady bought fewer ads; Evans has not advertised on broadcast channels since April 30.
Evans aide Tim Spreitzer said the campaign had diverted money to radio ads, direct mail, and get-out-the-vote efforts. "We think this is going to be won in the field on Tuesday," he said.
Knox booked $904,000 worth of TV time for the final week, bringing his total to nearly $10 million. Nutter bought $777,000 of time, station records showed.
A typical adult TV viewer will have seen a Knox ad about 18 times in the campaign's final week - and a Nutter ad about 16 times, based on average ratings. They will have seen five Fattah ads and two Brady ads.
Knox, seeking to regain his lead, barraged mailboxes with leaflets bashing Nutter, using a fuzzy, unflattering photo of the front-runner and labeling him "part of the Philadelphia's failed political system" with ties to "corrupt politicians." The mailings note that Nutter spent three months after leaving Council on the payroll of a firm with a Council contract.
Fattah attacked Nutter's other flank, raising concerns that Nutter's plan to have police "stop and frisk" people suspected of carrying illegal guns could lead to racial profiling.
On Friday, Nutter launched a counterattack on Knox, airing an ad quoting editorials that say the millionaire businessman and former deputy mayor is unsuited to run the city. "Don't let Tom Knox's money buy the election," the ad concludes. "Philadelphia deserves better."
Fattah strategists hope their campaign squeaks in "under the radar" as Knox and Nutter seek to damage each other.
Fattah's voter-turnout effort began in March, when workers first fanned out to knock on doors of likely supporters identified in past campaigns. "We go out seven days a week," field director Donald Redmond said.
On Tuesday, Redmond wore a Yankees cap and jeans as he dispatched 60 workers in seven vans from a lot at Broad Street and Girard Avenue - one of five spots citywide where Fattah workers gathered, as they had every day for weeks.
Skeptics note that it's easier to turn out votes when the foe is a Republican, and harder in an intraparty fight.
"The slice of the total vote pie that exists has to be much more precisely understood," field coordinator Tom Lindenfeld said. "Who you appeal to and go after is much more defined, because the number of people who are going to vote is that much smaller."
On Tuesday, the campaign plans to field 2,500 workers - and 260 vans.
Brady said he would have 3,000 seasoned pros working, from the party he heads and the myriad unions supporting him - four workers per polling place. "We've got them in all the right places," he said.
Howard Cain, a consultant on Brady's Election Day effort, said union households had "been hit with mail and phone calls telling them how important it is for Brady to get elected."
For two weeks, all the candidates have stepped up appearances, leaving behind the forums and debates for as much personal contact as possible. That was why Brady spent an hour Thursday in the steamy transit terminal at Bridge and Pratt in Frankford, shaking hands as people streamed up and down the El platform's stairs.
"It sounds crazy, but I love this stuff. It picks me up," he said, easing from one side of the hall to the other in front of the turnstiles, dispensing hugs and handshakes, posing for photos. Several people recognized him and greeted him like a pal.
"I'm the fiancee of a police officer, and I'll feel better with Bob in charge when my husband is out on the street," said Evelyn Hudson, 46, who lives in Overbrook. "Bob seems like the kind of guy who'll stand up and give it to you straight."
Knox's well-funded campaign claimed to have made 250,000 phone calls and knocked on about 70,000 doors to identify supporters. Manager Josh Morrow said 2,500 volunteers would mobilize Tuesday - plus 4,000 from the electrical workers' union.
"It's a mini-military operation," Morrow said. "We had to create an organization from the ground. . . . Chaka Fattah will be able to yank every voter in West Philadelphia . . . and chances are three out of five will vote for him. We don't have that base. We only want to pull out voters who will vote for us."
Nutter has never had a large traditional street organization, but he has attracted zealous volunteers, with an estimated 4,000 signed up for Tuesday.
"It's going to be Day of the Living Deaniacs, walking around with their Starbucks lattes saying, 'Nutter, Nutter, Nutter,' " sneered one political consultant, harking back to erstwhile presidential candidate Howard Dean's admirers. "They just don't have the infrastructure."
Then again, Nutter might not need it as much. Polls indicate his core supporters are more affluent and educated - ergo, more likely to vote.
Nutter said Friday: "I'd take passionate people, committed to a campaign, over anyone else out there."
To view a slide show on each of the candidates, along with their profiles, campaign promises and more, go to http://go.philly.com/mayor
On Election Day go to philly.com for updated coverage of the race.